Why PAFs have solid cores and screws?

[Flick]

Hi,

I'm a new member and I apologize in advance if I ask some questions that have already been discussed.

I just started doing my research to pursue a new interest, winding pikups.

My first 2 questions:

I was always wondering why PAF pickups have solid cores on one bobbin and adjustable screws on the other one.

Also, why are the two PAF pickups facing away from each other, which the screws closer to the bridge on the bridge pickup and the screws closer to the neck on the neck pickup?

Thanks...

[Mike Sulzer]

For continuity of appearance with Gibson's previous product, the p-90. Selecting a screw that has the same response to magnetic fields as the slugs (so that hum bucking is retained as well as reasonably similar sensitivity) is an extra design task and manufacturing inconvenience. Not what an engineer would want to do. As for your second question, that is probably mostly an appearance issue as well.

Hi,

I'm a new member and I apologize in advance if I ask some questions that have already been discussed.

I just started doing my research to pursue a new interest, winding pikups.

My first 2 questions:

I was always wondering why PAF pickups have solid cores on one bobbin and adjustable screws on the other one.

Also, why are the two PAF pickups facing away from each other, which the screws closer to the bridge on the bridge pickup and the screws closer to the neck on the neck pickup?

Thanks...

[Flick]

Oh, I see. So there's no technical reason. It's something I was always wondering about.

Thanks for your reply, Mike.

[copperheadroads]

Hi,




Also, why are the two PAF pickups facing away from each other, which the screws closer to the bridge on the bridge pickup and the screws closer to the neck on the neck pickup?

Thanks...

when Seymour asked Seth about the orientation, Seth said they just thought it looked better that way. There's no "science" to the way Gibson does it.
Though it will sound different if you turn the pickup the other way .

[Chuck H]

FoSelecting a screw that has the same response to magnetic fields as the slugs (so that hum bucking is retained as well as reasonably similar sensitivity)

I thought that the humbucking efficiency was related to the coils acting as equal inductors regardless of the static magnetic field.?. In that case the screws and poles would need to affect the coils in a similar way acting as inductor cores. But I'd love to learn more if the actual magnetic field in the coils affects humbucking properties.

[Mike Sulzer]

I thought that the humbucking efficiency was related to the coils acting as equal inductors regardless of the static magnetic field.?. In that case the screws and poles would need to affect the coils in a similar way acting as inductor cores. But I'd love to learn more if the actual magnetic field in the coils affects humbucking properties.

It is not static magnetic fields I mentioned, but those at 60 Hz and harmonics that cause hum. If the coils do not have the same sensitivity to hum, it cannot be canceled, and the steel in the coil affects the sensitivity.

In any case, it is not necessary for the inductances to be the same in order to cancel hum (although making identical coils does achieve both). Consider the dummy coil system where in one implementation a very large coil with few turns is used to get the same sensitivity to hum fields but maintain lower inductance than the pickup coil.

[jonson]

In answer to your first question. Seth designed the paf to have solid cores on both coils and there are pics of this on the net fully covered but indented where the poles are. Gibson decided on adjusting screws on one coil as a sales point to be ahead of the others.

[Joe Gwinn]

I thought that the humbucking efficiency was related to the coils acting as equal inductors regardless of the static magnetic field.?. In that case the screws and poles would need to affect the coils in a similar way acting as inductor cores. But I'd love to learn more if the actual magnetic field in the coils affects humbucking properties.

It is not the inductance, it's the area-turns product of the coils. This is what controls the sensitivity to external fields.

With an air-core coil, the area-turns product is N times the area of the average turn, where N is the number of turns.

Note that while area-turns product varies as N, the inductance varies as N squared, so inductance can only be used when comparing nearly identical coil designs.

With an iron-core or ferrite-core coil, the air-coil area-turns product is multiplied by the effective permeability of the core. This is difficult to compute, and so is usually measured.